Open Surgery is still the standard technique for most surgical procedures. It has been used by the medical community for several decades and consists of performing the surgical tasks by a long incision in the abdomen, through which traditional surgical tools are inserted. However, due to the long incision, this approach is extremely invasive for the patients, resulting in substantial blood loss during the surgery and long and painful recovery periods at the hospital.
In order to reduce the invasiveness of open surgery, laparoscopy, a minimally invasive technique, was developed. Instead of a single long incision, four to five small incisions are made in the patient through which long and thin surgical instruments and endoscopic cameras are inserted. Because of the low invasiveness, this technique reduces blood loss and shortens hospital stays and pain. When performed by experienced surgeons, this technique can attain clinical outcomes similar to Open Surgery. However, despite the above-mentioned advantages, laparoscopy requires extremely advanced surgeon skills to manipulate the rigid and long instrumentation. The entry incision acts as a point of rotation, decreasing the freedom for positioning and orientating the instruments inside the patient. The movements of the surgeon's hand about this incision are inverted and scaled-up relative to the instrument tip (“fulcrum effect”), which removes dexterity, sensibility and magnifies the tremors of the surgeon hands. In addition, these long and straight instruments force the surgeons to work in a uncomfortable posture for hands, arms and body, which can be tremendously tiring during several hours of operation. Therefore, due to these drawbacks of the laparoscopic instrumentation, these minimally invasive techniques are mainly limited to use in simple surgeries, while only a small minority of surgeons is able to use them in complex procedures.
To overcome these limitations, surgical robotic systems were developed to provide an easier-to-use approach to complex minimally invasive surgeries. By means of a computerized robotic interface, these systems enable the performance of a remote laparoscopy where the surgeon sits at a console manipulating two master manipulators to perform the operation through several small incisions. Like laparoscopy, the robotic approach is also minimally invasive, bringing several advantages over open surgery in terms of pain, blood loss, and recovery time. In addition, it also offers better ergonomy for the surgeon compared to open and laparoscopic techniques. However, although being technically easier, Robotic Surgery brings several negative aspects. A major disadvantage of these systems is related with the extremely high complexity of the existing robotic devices, which are composed by complex mechatronic systems, leading to huge costs of acquisition and maintenance, which are not affordable for the majority of surgical departments worldwide. Another drawback of these systems comes from the fact that current surgical robots are voluminous, competing for precious space within the operating room environment and significantly increasing preparation time. Access to the patient is thus impaired, which, together with the lack of force-feedback, raises safety concerns.
WO9743942, WO9825666 and US2010011900 disclose a robotic tele-operated surgical instrument, designed to replicate surgeons' hand movements inside the patient's body. By means of a computerized, robotic interface, it enables the performance of a remote Laparoscopy where the surgeon sits at a console manipulating two joysticks to perform the operation through several small incisions. However, this system does not have autonomy or artificial intelligence, being essentially a sophisticated tool fully controlled by the surgeon. The control commands are transmitted between the robotic master and robotic slave by a complex computer-controlled mechatronic system, which is extremely costly to produce and maintain and difficult to use by the hospital staff.
WO 2008130235 discloses a less complex mechanical manipulator for an instrument for minimally invasive surgery, having at a proximal end a handle for operating the instrument connected at a distal end of the manipulator. A parallelogram construction is provided between the proximal end and the distal end for guaranteeing an unambiguous position relationship between the handle and the instrument. This parallelogram construction is coupled with a system of bars for controlling the position of the parallelogram construction. The bars of the system are connected to the parallelogram construction as well as to each other by means of cardan joints.
The parallelogram constraint imposed by this mechanical manipulator renders difficult to obtain a scaled ratio other than 1:1 between the amplitude of the movements applied on the handle of this manipulator and the amplitude of the movements reproduced by the instrument connected at the distal end of the manipulator. This reduces the precision of the manipulator which is at the utmost importance for surgical intervention.
Furthermore, the handle of the manipulator of WO 2008130235 is connected to an extended arm which is slidably mounted along a guiding element. This ensures that the extended arm always translates along its longitudinal axis so that the instrument always translates along a virtual axis parallel to the longitudinal axis of said extended arm. The guiding element is eccentrically mounted rotatably on a supporting structure which causes the instrument to rotate around a stationary single point at a certain distance of this point which is not adequate when constraints are imposed by an incision realized on a patient. In addition, due to the high inertia of the rigid elements of the parallelogram construction, this mechanical manipulator provides poor haptic transparency.
Several other mechanical systems have been developed for remote manipulation in radioactive environments and are disclosed in several documents, such as US2846084. However, although the system disclosed in this document comprises a master-slave architecture, its dimensions, weight and kinematics are not suitable for minimally invasive surgical applications.
Accordingly, an aim of the present invention is to provide a mechanical teleoperated device preferably for minimally invasive surgical procedures capable of manipulating surgical instruments with higher precision, increased haptic transparency and which overcomes the aforementioned drawbacks of the prior art.
Another aim of the present invention is to provide a mechanical teleoperated device which can be easily adapted to be used for other forms of minimally invasive surgery as well as open surgery or procedures on MRi environments.